PHOTOSHOP - using one light with multiple exposures

Say you only have one flash head, or bulb light, yet you want to be able to ‘shape’ the lighting on a subject to make it more dramatic? We will use this Nikon D3 camera as an example. I took a number of frames with one flash head but moved to different positions. Taking one frame from each with my camera on a tripod. Neither my camera or the D3 moved. In Photoshop I made a layer stack of 4 of these images, I then erased the bits of each I wanted to include. I have only included two of the frames here out of the four that I took, but it gives an idea as to how it works. The next gallery offers a way of changing the background.
1. Flat overall lighting with one light moved to four different positions. One frame taken of each position against a green-screen background.
2. Rear flash only.
3. Front side flash only.
4. Final rendering plus green desaturated background. Note the dramatic difference in lighting compared on (1).

1. Original shot against green screen background with an overall lighting treatment (one light)

2. Rear light only

3. Front side light only

4. Final treatment (one light in four different positions)

Background replacement

Two methods of changing the background. Cutting it out and replacing it, or by Selective Colour to desaturate it.

Original frame shot against green screen

1. Unlocking the background layer

2. Selecting the green with the magic wand, then expanding the pixels closer to the camera

2B. Modify the pixels to expand them. SELECT - MODIFY - EXPAND 1 pixel

2D. Pixels 'jumped' by one pixel closer to the camera

2E. Similar pixels selected

2C. Pixels about to be expanded

3. Cutting the green pixels away

4. Selective colour remove green spill from camera

4B. Note the green on the lens hood

5. New grey layer as background

6. New two tone gradient as background

7. Or two tone blue and white gradient

8. Solid blue

9. Increasing red if you need to

This is a quick and easy way to add that extra dimension to product shots, in fact anything where the background is a clean colour that separates the subject allowing it to be removed. It gives you a lot of flexibility as a location photographer.

All photography and information © Jon Davison 2021

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